From March last year, the project, which lasted more than six months improved, to large-scale promotion this year, the company single-row crossed roller slewing bearing a large thin-walled bearing outer quenching and tempering process improvements achieved a breakthrough: reducing distortion, reduce scrap rates, removal of all seized and subsequent shaping, to the stress process, saving time and labor costs, economic benefits are considerable.
As soon as possible in order to break this bottleneck, last March, the company has set up a project team bearing the main research content is the medium and large thin-walled bearing outer heat deformation control. First, in the application of the device, the project team proposed to replace the new roller furnace mesh belt furnace. Because the former use of radiation heating, the temperature can be precisely controlled, better heating uniformity, can greatly reduce the amount of deformation. Meanwhile, the roller furnace with nitrogen and propane as a protective atmosphere that allows oxidation products through appropriate to achieve the desired hardness, to meet different customer requirements.
The new production line roller furnace into operation after a period of time, the question came up: the workpiece into the furnace to be of special baskets, large deformation proportion remains high specification products. The project team developed a project implementation plan, schedule lists: the first phase of small batch processing, such as the promotion of a wide range of process maturity and then, at the same time according to the time schedule, to reduce the amount of deformation also made clear the indicator. Through several experiments, on the one hand, optimized display mode, eventually completely without baskets directly to the workpiece placed on the stove, so a single volume into the furnace to increase production efficiency also will increase; on the other hand, the project team By replacing the quenching oil, in accordance with the product model to set the stirrer speed and time, so that the quenching oil is more evenly distributed in the surface, can be achieved to ensure the hardness after quenching and qualification requirements of the microstructure, in order to better control the amount of deformation . After these improvements reflect subsequent grinding staff is very good. They say that good quality new processing technology, especially small sag, the rejection rate is almost zero.
Bearing outer ring after quenching and tempering after heat treatment, can improve product strength, hardness, wear resistance, fatigue strength and toughness. Previously, the company slewing ring bearings technology equipment used mesh belt furnace and furnace roller quenching, tempering, there is always some distortion problems affecting the efficiency quality. Especially greater than 150 mm in outer diameter of the large product, the deformation is more pronounced. In recent years, bearing the company's market has been expanding from the traditional automotive industry market more towards wind power bearings, machine tool bearings and other emerging industries range, product specifications growing, medium and large bearing outer ring more and more . How to solve the problem of a product deformation caused by the traditional process, the company has become an urgent need to address the "big obstacle."
Because deformation meet the requirements, the vast majority of medium and large companies are now bearing products do not need a full inspection, plus reduce the stress to both shaping and procedures, in the same middle class, the product circulation accelerated greatly improved production efficiency. Furthermore, the bearing outer ring taper becomes smaller, the subsequent grinding allowance is also reduced. In terms of cost, plastic, five employees to streamline the inspection process, at least an annual payroll savings of 200,000 yuan; the same time, to reduce stress and subsequent shaping of the original annual electricity use of 40,000 yuan, the benefits of these savings are very impressive .
After six months of exploration and constantly try to verify quenched by the end of last year, bearing the company double row ball slewing bearing a large amount of deformation of thin-walled outer ring has basically met the technical criteria deformation proportion dropped to 80% more than before.
Today, the company is working to transform the original roller furnace, so that you can promote the use of new technology as soon as possible. Heat treatment unit plan.
